There are many complains about Msmpeng.exe CPU problems as well as other problems reported with this file. The following post reviews the common causes to these problems and what should be done in order to resolve them.
This process is part of Windows Defender anti-spyware program.
It used to be embedded by default in Windows Vista and you could have downloaded it for free from Microsoft’s site and use it with other versions of Windows.
Common known problems
(1) Might eat up lots of CPU (50%-100%)
(2) Causes significant system slowdowns and poor performance
(2) Causes extremely slow system bootups
Common causes to this problem
(1) Conflicts between this process and other processes (especially security related), drivers, and services.
(2) Windows Defender is currently scanning your HD…
(3) Other errors related to Msmpeng.exe.
Step-by-step repair guide:
(1) Change Windows Defender scheduled auto-scans
Yes - when Windows Defender automatically scans your HD, it might consume much of your CPU, so simply open Windows Defender’s settings and change the scheduled auto-scans to a more convenient time so it won’t interfere your work.
If this doesn’t solve the problem, continue to step #2.
(2) Check for any conflicts with other services
If you have any other security related programs, disable the first one and see if the problem had stopped, if not, do the same with the next programs etc. If the problem continues, use the following Windows errors repair tool – it’ll enable you to manage all your processes and startup items. Try to isolate the problematic process or startup items as explained here.
If you’ve found no such conflicts – continue to the next step.
(3) Scan for Msmpeng.exe related errors
Use this Windows errors repair tool to scan your HD – it’ll tell you whether there are any open issues or errors related to this process.